package com.mrd.weixinpay.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class MD5Util {

	private static String byteArrayToHexString(byte b[]) {
		StringBuffer resultSb = new StringBuffer();
		for(int i = 0;i < b.length;i++)
			resultSb.append(byteToHexString(b[i]));

		return resultSb.toString();
	}

	private static String byteToHexString(byte b) {
		int n = b;
		if(n < 0)
			n += 256;
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	public static String MD5Encode(String origin,String charsetname) {
		String resultString = null;
		try {
			resultString = new String(origin);
			MessageDigest md = MessageDigest.getInstance("MD5");
			if(charsetname == null || "".equals(charsetname))
				resultString = byteArrayToHexString(md.digest(resultString.getBytes()));
			else
				resultString = byteArrayToHexString(md.digest(resultString.getBytes(charsetname)));
		} catch (Exception exception) {}
		return resultString;
	}

	private static final String	hexDigits[]	= {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
	        "a", "b", "c", "d", "e", "f"	};

	// MD5算法修改
	public static String getMD5(String source) {
		String str = "";
		try {
			MessageDigest md = MessageDigest.getInstance("MD5");
			md.update(source.getBytes());
			byte b[] = md.digest();
			int i;
			StringBuffer buf = new StringBuffer("");
			for(int offset = 0;offset < b.length;offset++) {
				i = b[offset];
				if(i < 0)
					i += 256;
				if(i < 16)
					buf.append("0");
				buf.append(Integer.toHexString(i));
			}
			str = buf.toString();
			// System.out.println("result: " + buf.toString());// 32位的加密
			// System.out.println("result: " + buf.toString().substring(8, 24));// 16位的加密
		} catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return str;

	}

}

